The present invention is directed generally to a security system, and more specifically to a security system having a sensor, a unidirectional signaling and passive transmitter and a receiver unit.
A variety of security systems and personal monitoring systems presently exist.
In one class of monitoring systems the transmitter unit is carried as an active device by a person or employee. The signal from the transmitter may be received by the sensor unit which may indicate that a person or object is going through a door or similar portal. Once the sensor has picked up the signal, it relays a second signal to an alarm or similar type device.
In a second class of security systems or personal monitoring systems, a user or person carries a passive device which receives signals and retransmits the signals when the person is in a predetermined range of a transmitter. Still other devices rely upon a pressure pad which may be stepped upon, or triggered by the opening of a door.
These personnel and security systems have several disadvantages, such as: (1) they do not provide advanced warning that a monitored person may be about to go through a passageway; (2) the systems can be defeated by a person who quickly proceeds through a passageway; (3) the systems are often susceptible to failure due to the monitoring capability of the system, and timing intervals between sensing by the sensor and relay from the transmitter to the receiver; (4) the system uses a variety of transmission signals from sensor to transmitter to receiver; (5) the systems are dual direction signalling in transmission and lack specificity in the actual signal which is transmitted and therefore, in many cases, fail due to a temporary malfunction because of inadequate warning, confusion of signals, or interferences by unrelated signals in the vicinity. These and other difficulties experienced with the prior art devices have been obviated in a novel manner by the present invention.
It is therefore, an outstanding object of the invention to provide a security system which is wireless and which utilizes a one way signal transmission from sensor to transmitter to receiver.
Another object of this invention is the provision of a security system in which the user passively carries the receiving unit while the transmitter unit and sensor are stationed in a defined area to be monitored.
A further object of the present invention is the provision of a security system which can minimize the possibility of bodily harm to a home owner who is unexpectantly confronted by an intruder.
It is another object of the present invention to provide a security system which operates passively to avoid alerting the intruder that he has been detected by a sensor unit.
A still further object of the invention is the provision of a security system which provides a sole and unidirectional transmission signal from a radio frequency transmitter to a receiver unit.
It is a further object of the invention to provide a security system with a sensor, a transmitter having a detection memory, status collector, encoder and radio frequency transmitter which can encode and transmit a defined and encoded signal and which can be received only by a receiver capable of decoding the encoded radio frequency transmission.
With these and other objects in view, as will be apparent to those skilled in the art, the invention resides in the combination of parts set forth in the specification and covered by the claims appended hereto.